1. Field of the Invention
Devices and methods consistent with the present invention relate to a service relay device, a service receiver receiving the relayed service signal, and methods thereof, and more particularly, to a service relay device which relays the service signal from a plurality of subsequent frequency channels, a service receiver which receives the relayed service signal, and methods thereof.
2. Description of the Related Art
The rapid development in the field of digital broadcast has made a variety of services available through broadcast receivers. The broadcast service is transmitted from a broadcast station or relayed from a relay device, to be received in the receivers of viewers. However, the problem is that not all viewers receive the service under the same conditions. Specifically, some viewers may be in a fringe area where the reception is poor due to ambient obstacles, such as high-rise buildings, mountains, or the like. The service relay devices are thus provided to enable smooth reception of the signals in the fringe areas.
FIG. 1 illustrates the structure of a related art service network with which a service relay device is provided. Referring to FIG. 1, a base station 10 covers ‘Region 1’ which is a wide area and which includes ‘Region 2’ which is a fringe area.
The service network thus includes a service relay device 20 to manage signal transfer to the fringe area. Accordingly, the service relay device 20 broadcasts a service signal transmitted from the base station 10 to Region 2 via a different frequency channel.
FIG. 2 illustrates the characteristics of a frequency channel in Region 1 and Region 2. If the base station 10 uses an A1 frequency channel which has a mean frequency ‘A1’, the service relay device 20 uses a B1 frequency channel. The different frequency channels are used even to transfer the same service, in order to avoid interferences due to differences in the paths, or the like.
In the developing digital broadcast technology, it has been suggested to transfer one single service through a variety of different frequency channels. Generally, the data size differs depending on the service types. Accordingly, if a broadcast station uses only one unique frequency channel allocated thereto, the station will have difficulty of transferring a large volume of data within a predetermined time. In order to address this problem, the method of frequency channel exchange among the broadcast stations has been proposed.
In the above method, a receiver, such as a TV, has to know the information about a new frequency channel if the frequency channel is exchanged. Accordingly, the broadcast station adds the information about a new frequency channel to a service signal and transfers the service signal along with the information.
Meanwhile, the service relay 20 covering the fringe area as shown in FIG. 1 receives a service signal and broadcasts the received signal through a different frequency channel. If the frequency channel is exchanged, the service relay device 20 is unable to relay the service signals received from a plurality of subsequent frequency channels. As a result, the fringe area does not have a good signal reception.